The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods and structures to form DC/DC converters that utilized charge pump circuits to control the output voltage formed by the converter. These converters typically monitored the value of the output voltage and switched the mode of the charge pump circuit in order to regulate the value of the output voltage. Typically, a feedback voltage that was representative of the value of the output voltage was compared to a reference voltage and the mode of the charge pump circuit would be changed if the feedback voltage fell below the value of the reference voltage. One example of such a DC/DC converter was disclosed in U.S. Pat. No. 6,411,531 that issued to Nork et al on Jun. 25, 2002. One problem with these prior DC/DC converters was the area consumed by the reference voltage circuit, the comparator, and the other closed loop elements. The circuits generally required a large area on the semiconductor die on which the circuit was formed thereby increasing the cost of the converter circuit.
Accordingly, it is desirable to have a controller circuit that utilizes less die area and that has a lower cost.
For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action.